Fuse construction



Jan. 31, 1939. w. o. scHULTZ FUSE CONSTRUCTION 2 Sheets-Sheet l FiledNov. 20, 1956 @u w w H 9 f4 z y girl' Z@ l:

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INVENTOR. h//zz/A/lf 0 5ml/fz w. o. 'scHULTz 2,145,375

FUSE CONSTRUCTION Jan. 3l, 1939-.

Filed Nov. 20, 1936 2 Sheets-Sheet 2 INVENT OR.

Patented Jan. 31, 1939 UNITED STATES PATENT OFFICE 2,145,375 FUSECONSTRUCTION Application November 20, 1936, Serial No. 111,827

16 Claims.

This invention relates to a fuse construction and is particularlydirected to a fuse construction associated with a transformer or otherelectrical device.

This invention is intended to provide a fuse construction which isparticularly useful on a single bushing transformer which is now quitecommon for rural service. These transformers are made up with only oneprimary bushing, the other side of the primary Winding being solidlygrounded to the transformer case.

Objects of this invention areto provide a fuse construction in which thefuse structure is carried by or Supported from the transformer bushing,in which an expulsion fuse tube is so mounted that the expelled gasesand metallic vapors are directed away from the casing.

Further objects are to provide a novel form of construction in which thefuse tube performs a two-fold function, as it acts as an insulatingmember to insulate one contact from the other contact and also acts as aSupport for the spark gap or surge protecting means, and in which theSpark gap carried by the fuse tube is of the expulsion tube type and isassociated with a. Stationary electrode to insure proper Spacing,irrespective of inaccuracies in the precise alignment of the parts.Further objects are to provide a construction in which an expulsion typeof fuse is readily applied to or removed from the contact of a Singlebushing transformer, in which provision is made for detachably lockingthe fuse construction to the contact of the single bushing transformer,in which provision is made for detachably connecting the' opposite endof the fuse tube to a live conductor, and in which the clamping meansfor attaching or detaching the fuse tube and for connecting it to a linewire may be operated by a switch stick, the fuse itself being thereafterremoved either by tongs or by hand.

Further objects are to provide a construction of combined fuse tube andsurge protection means which is cheap to manufacture and simple inconstruction and which has very few parts.

Embodiments of the invention are shown in the accompanying drawings, inwhich:

Figure l is a side elevation, partly in Section, showing the fuse tubein place.

Figure 2 is a horizontal fragmentary view; with parts in section. v i

Figure 3 is a view of a modified form of construction, such viewcorresponding'to Figure 2.

Referring to Figures 1 and 2, it will be seen that the transformerhousing I. 'which 1S of (Cl. Z110-115) metal, is provided with a rigidlymounted, insulating bushing 2 projecting upwardly therefrom andterminating in a threaded Acontact stud 3. This contact stud 3 receivesthe conductor from one side of the primary of the transformer and isinterlocked with the rigidly mounted insulating bushing 2. This contactstud receives the cap nut 4 which carries the contact or lug 5. Thiscontact 5- is of rectangular construction, as is apparent from Figure 2.

The fuse tube 6 is provided with an apertured contact I at one endprovided with a downwardly extending, internally threaded boss or sleeve8 and with an upwardly projecting connector receiving bar or portion 9.The other end of the fuse tube or the effective open end thereof isprovided with a contact I0 which has an integrally formed, laterallyoffset projection II provided with a rectangular aperture I2 for thereception of the lug or contact 5. The member II is provided with alocking screw member I3 equipped with an eyelet I4 so that it may behandled by a switch stick. The contact I0 also carries a threaded studI5 which receives the thumb nut I6 by means of which the leader I1 ofthe fuse link may be attached.

The fuse link may comprise a small size strainresisting wire I8, whichmay be. of iron or steel, and a. section I9 formed of low fusible alloy.A Spring holds the strain wire I8 in tension. The other end of thespring 20 is attached to a stud 2l provided with a head 22 bearingagainst the outer lside of the contact 1, as shown most 4clearly inFigure 1.

An insulating sleeve 23 is threaded into the boss 8 and an upperelectrode or Spark member 24 is secured to the contact I and projectsdownwardly into the tube or sleeve 23. The rod or spark member 24 is.spaced from the side walls of the sleeve 23 and also stops a.considerable distance above the lower end of the sleeve 23. The lowerelectrode or surge yprotection means or spark gap comprises a stem 25terminating in an upper disk 26, the disk presenting substantial areatowards the tube 23 so that precise alignment of the parts is notnecessary, as small variations will be taken care of as the tube 23 willunder all conditions be positioned above the disk 26.

A leader 21 is clamped by means of the split connector 28 to the stem 9of the contact 1. The other end of the leader is secured to a clampingmember or live wire clamp 28 which may comprise an upper hooklike member29 adapted to hook over the line wire 30, and a lower clamping screw 3Iprovided with an eyelet portion 32. When an overload occurs, the sectionI9 formed of a low melting point alloy is ruptured and immediately thestrain wire I8 is ruptured. The

spring 20 increases the separation of the parts and the violentlyexpelled gases blow any remaining portion of the leader or fusiblesections I8 and I9 outwardly from the fuse tube, thus insuringextinction of the arc within the tube and rapid breaking of the circuit.

Thereafter the fuse tube may be detached from the contact 5 or supportby means of a switch stick cooperating with the eyelet I4 and the `clampeyelet 32 may similarly be operated by a switch stick to detach theleader 21 from the live wire or line wire 30. Y

The device may be re-fused and may be re' placed in the reverse manner.

It is to be noted that normally the head 22 of the fuse link, see Figurel, closes the aperture in the contact 1 and is held in engagement withsuch contact by means of the spring 20.

It will be seen that surge protection is provided under all conditions,even after the fuse has ruptured, as any surge that may occur will betaken care of by the spark gap members 24 and 26. The arc will beimmediately extinguished as the hot gases are violently blown from thetube 23 and thus extinguish the arc.

The fuse tube itself forms the support for the spark gap member and alsoacts as an insulating spacing member for the two contacts connected bythe fuse link. Also it is to be noted that the fuse tube is very easilyapplied to or removed from the transformer.

Other types of fuse tubes could be employed, for example the type shownin Figure 3. In this form of the invention, the fuse tube 33 is providedwith a contact 34 which has a threaded sleeve equipped with a cap nut orclamping nut 35 which clamps the head or button 36 of the fuse link tothe contact 34. The fusible section is indicated at 31 and the leader at38.

'Ihis leader is clamped beneath the thumb nut I6 which is threaded onthe stem I5' of the contact member III'. This contact member has arectangular slot for the-reception of. the contact 5 and may be lockedthereto by means of the screw member or clamping member I3' which isprovided with the eyelet portion I4', all as previously described.

'I'he fuse tube may be similar in other respects to the form shown inFigures 1 and 2 and carries a spark gap member, as previously described,such member, however, not being visible in Figure 3.

An overload causes the fuse to act as an ordinary type of expulsionfuse. This form of the invention may be applied to and removed from thetransformer in the same manner as that previously described.

It will be seen thata novel form of fuse construction has been providedwhich is particularly adapted for use on single bushing transformers andwhich is so made that a minimum number of parts are employed, the fusetube acting in the double capacity of the insulator for spacing thecontacts and also for the support for the spark gap or surge protectionmeans.

Although this invention has been described in considerable detail, it isto be understood that such description is intended as illustrativerather than limiting, as the invention may be variously 1. In anapparatus of the class described, al

stationary contact, supporting means for said stationary contact, a fusetube having a contact provided with means cooperating with saidstationary contact, means for removably holding the means whichcooperates with said stationary contact to said stationary contact, saidfuse tube being electrically connected to and mechanically supportedfrom said stationary contact, said fuse tube including an insulatingtubular body portion projecting outwardly from the contact of said fusetube and having a terminal contact held in spaced relation to saidsupporting means and the iirst mentioned contact of said fuse tube, anda fuse link joining the contacts of said fuse tube.

2. In anapparatus of the class described, a stationary contact,supporting means for said stationary contact, a fuse tube having acontact provided with means cooperating with said stationary contact,means for removably holding theI means which cooperates with saidstationary contact to said stationary contact, said fuse tube beingelectrically connected to and mechanically supported from saidstationary contact, said fuse tube including an insulating tubular bodyportion projecting outwardly from the contact of'said fuse tube andhaving a terminal contact held in spaced relation to said supportingmeans and the rst mentioned contact of said fuse tube, a fuse linkjoining the contacts of said fuse tube, and conductor receiving meanscarried by said ter- \mina1 contact. 3. lIn an apparatus of the classdescribed, supporting means, a stationary contact carried by saidsupporting means, a fuse tube having a contact provided with meanscooperating with said stationary contact, means for removably holdingthe means which cooperates with said stationary contact to saidstationary contact, said fuse. tube being electrically connected to andmechanically supported from said stationary contact, bsaid fuse tubeincluding an insulating tubular body portion projecting outwardly fromthe contact of said fuse tube and having a terminal contact held inspaced relation to said supporting means and the rst mentioned contactof said fuse tube, a fuse link joining the contacts of said fuse tube,and spark gap means, one portion of said spark gap means being supportedfrom and carried by the terminal contact of said fuse tube and the otherportion of said spark gap means being carried by said supporting means.Y

4. In an apparatus of the class described, supporting means, astationary contact carried by said supporting means, a fuse tube havinga, contact provided with means cooperating with said stationary contact,means for removably holding the means which cooperates with saidstationary contact to said stationary contact, said fuse tube beingelectrically connected to and mechanically supported from saidstationary contact, said fuse tube including an insulating tubular bodyportion projecting outwardly from the contact of said fuse tube andhaving a terminal contact held in spaced relation to said supportingmeans and the iirst mentioned contact of said fuse tube, a fuse linkjoining the contacts of said fuse tube, and spark gap means formed oftwo parts, one part consisting of a sleeve and an internal electrodecarried by said terminal contact and the other part consisting of a disklike member carried by said supporting means and spaced from saidsleeve, said internal electrode being spaced a material distance fromthe lower end o1' said sleeve.

5. In an apparatus of the class described, supporting means, aninsulating bushing carried by said supporting means and forming aunitary portion with said supporting means, a rectangular stationarycontact carried by said insulating bushing, a fuse constructioncomprising a fuse tube having a first and a second contact, said firstcontact having a rectangular aperture for the reception of saidstationary contact, gripping means for holding said rst contact to saidstationary contact to electrically connect said fuse tube thereto and tomechanically support said fuse tube therefrom with said fuse tubeprojecting from said stationary contact, conductor receiving meansconnected to said second contact, and a fuse link joining said first andsecond contacts.

6. In an apparatus of the class described, supporting means, aninsulating bushing carried by said supporting means and forming aunitary portion with said supporting means, a rectangular stationarycontact carried by said insulating bushing, a fuse constructioncomprising a fuse tube having a first and a second contact, said firstcontact having a rectangular aperture for the reception of saidstationary contact, gripping means for holding said rst contact to said`stationary contact to electrically connect said fuse tube thereto andto mechanically support said fuse tube therefrom with said fuse tubeprojecting laterally from said stationary contact, conductor receivingmeans connected to said second contact, and a fuse link joining saidiirst and second contacts.

7. In an apparatus of the class described, vsupporting means, aninsulating bushing carried by said supporting means and forming aunitary portion with said supporting means, a rectangular stationarycontact carried by said insulating bushing, a fuse constructioncomprising a fuse tube having a first and a second contact, said iirstcontact having a rectangular aperture for the reception of saidstationary contact, gripfuse tube in spaced relation to said firstmentioned portion.

8. In an apparatus of the class described, supporting means, aninsulating bushing carried by said supporting means and forming aunitary portion with said supporting means, a rectangular stationarycontact carried by said insulating bushing, a fuse constructioncomprising a fuse tube having a first anda second contact, said rstcontact having a rectangular aperture for the reception of saidstationary contact, said first contact binding against said stationarycontact to electrically connect said fuse tube thereto and tomechanically support said fuse tube there- `from with said fuse tubeprojecting laterally from said stationary contact, conductor receivingmeans connected to said second contact, a fuse link joining said rst andsecond contacts, and spark gap means formed of two portions, one of saidportions being. carried oysalu supporting means and the other of saidportions being supported from the second contact of said fuse tube inspaced relation to said -iirst mentioned portion.

9. In an apparatus of the class described, supporting means, a bushingrigidly carried by said supporting means and projectingl therefrom andhaving a stationary contact, an expulsion fuse construction comprising afuse tube having a first and a second contact, said rst contact beingaperturyed for the reception of i said stationary contact, clampingmeans for locking said first contact to said stationary contact, saidfuse tube being mechanically supported by and extending from saidstationary'contact, a fuse link joining said first and second contacts,a iiexible leader connected lto said second contact, and line wireclamping means secured to said flexible leader.

10. In an apparatus of the class described, supporting means, a bushingrigidly carried by said supporting means and projecting therefrom, astationary contact carried by said bushing, a fuse construction, saidfuse construction comprising an expulsion fuse tube having a rst contactand a second contact, means for locking-said first contact to saidstationary contact, a fuse link joining said first and second contacts,line wire connecting means joined to said second contact, a spark gapmember rigidly carried by said second contact and projecting towardssaid supporting means, and a second spark gap member carried by saidsupporting means and presented towards said first spark gap member.-

11.1n an apparatus of the class described, supporting-means, aninsulating bushing projecting therefrom, a stationary Contact carried bysaid bushing, a fuse construction comprising a fuse tube having a firstcontact and a second contact,` said rst contact having an aperturedportion for the reception of said stationary contact, readily releasableclamping means for clamping said first contact to said stationarycontact, a fuse link extending from said second contact through saidfuse tube to said rst contact, a clamping nut carried by said firstcontact for clamping said fuse link, said fuse tube being mechanicallysupported from said stationary contact arid projecting laterallytherefrom, and detachable line wire connecting means connected to saidsecond contact.

l2. In an apparatus of the class described, supporting means, aninsulating bushing projecting therefrom, a stationary contact carried bysaid bushing, a fuse construction comprising a fuse tube having a rstcontact and a second contact, said first contact having an aperturedportion for the reception of said stationary contact, readily releasableclamping means for clamping said rst contact to said stationary contact,a fuse link extending from said second contact through said fuse tube tosaid first contact, a

clamping nut carried by said first contact forV spark gap being carriedby said supporting means and spaced from the end of said sleeve.

1 3. In an apparatus of the class described, supporting means, vaninsulating bushing projecting therefrom, a stationary contact carried bysaid bushing, a fuse construction comprising a fuse tube having a rstcontact and a second contact, said first contact having an apertured`portion for the reception of said stationary contact, means carried bysaid first contact for manipulation by a switch stick, said meanstemporarily locking said rst contact to said stationary contact, a fuselink extending fromtsaid second contact through said fuse tubeto saidrst contact, said fuse tube being mechanically supported from saidstationary contact and projecting laterally therefrom, a flexible leadersecured to said second contact, and line wire clamping means formanipulation by a switch stick, said line wire clamping means beingattached to said iiexible leader.

14. In an apparatus of the class described, supporting means, aninsulating bushing rigidly carried by said supportng meansand forming aunitary portion with said supporting means, a stationary contact carriedbyV and interlocking with said bushing to prevent rotation of saidstationary contact with respect to said bushing, a fuse constructioncomprising a fusetube having a iirst contact and a second contact, saidrst contact having means interlocking with said stationary contact .forsupporting said fuse tube from said stationary contact and forprecluding rotation of said fuse tube with reference to said stationarycontact, said fuse tube being electrically connected to said stationarycontact and mechanically supported laterally from said stationarycontact, conductor receiving means connected to said second contact, anda fuse link joining said first and second contacts.

15. In an apparatus of the class described,

40 supporting means, an insulating bushing rigidly connected to saidstationary contact and mechanically supported laterally from saidstationary l contact, conductor receiving means connected to said secondcontact, a fuse link joining said rst and second contacts, and spark gapmeans formed of two portions, one of said portions being carried by saidsupporting means and the other of said portions being supported fromsaid secondv contact of the fuse tube-in spaced relation totsaidfirstmentioned portion.

16. The combination of a rigidly mounted terminal'member and aninsulating bushing surrounding said member, a terminal cap rigidlymounted o'n said bushing and secured to said memberr said cap having arectangular contact lug, an expulsion/fuse tube having at'one end aterminal collar provided with a laterally projecting rectangularlyapertured sleeve receiving said lug and having at the other end aterminal collarprovided with an arcing rod projecting from said fusetube, said fuse tube projecting laterally from said bushing, aninsulating tube surrounding said rod, an arcing member adi jacent saidinsulating tube and spaced from said tube and rod, and connecting meansfor electricalf ly connecting said fuse tube with an electric line

